Ceiling suspensions for surgical microscopes are disclosed, for example, in the Zeiss publication entitled "Zeiss OPM 250F, 251F", brochure number 60-143-1. These ceiling suspensions have a configuration which includes a column suspended perpendicularly from the ceiling and a support arm pivotally mounted at right angles as well as a parallelogram arm pivotally connected for mounting the microscope. With this assembly, further degrees of freedom or rotation and inclination can be realized.
The arrangement has the following disadvantages. The ceiling of the operating room on which the support is suspended must have an especially high rigidity in order to prevent vibrations which can be transmitted to the support. The structural measures and requirements are complex especially for a subsequent installation in an operating room.
The L-shaped construction of the support column with the carrier arm and the parallelogram arm is very unfavorable with respect to vibration behavior and requires a correspondingly strong design for the swivel joint as well as for the column, support arm and parallelogram arm. The microscope can only be positioned in a circularly-shaped region around the central column; that is, the largest portion of the region of movement is practically unuseable and the most favorable case with respect to vibration for the position below the suspension is not realizable because of geometric reasons.
Arrangements for variably counterbalancing weight for the application of various configurations of the microscope and accessories of different weights complicate the structural configuration of the parallelogram arm.
The elevation to which the column extends downwardly is determined by the compromise between the mutually opposing requirements of floor clearance and comfortable operability of the operator-actuable elements mounted on the column and this compromise cannot be optimally configured because of the different body sizes of individual operators of the equipment.